1. Technical Field
The present disclosure relates to a speaker system using an open acoustic tube.
2. Description of the Related Art
In a speaker system for a vehicle, reproduction is demanded to be performed with sound volumes sufficient in a low frequency range to create powerful sounds. For this purpose, in a structure in which a speaker unit is attached to a closed type cabinet, reproduction has been performed with a sound pressure level in a low frequency range electrically corrected and thereby increased. For example, FIG. 9 is a conceptual diagram of a sound pressure frequency characteristic before and after the correction. FIG. 9 is a diagram illustrating sound pressure characteristics with respect to frequencies in a structure in which a speaker unit is attached to a closed type cabinet. In FIG. 9, the solid line represents a sound pressure characteristic with respect to frequencies when electrical correction is performed on a sound pressure level in a low frequency range and the dotted line represents a sound pressure characteristic with respect to frequencies when electrical correction is not performed on a sound pressure level in a low frequency range. When electrical correction is performed on a sound pressure level in a low frequency range, electrical amplification is performed on a band equal to or lower than the resonance frequency of the closed type cabinet determined by the caliber of the speaker unit and the internal volume of the closed type cabinet, whereby a sound pressure substantially equal to that in a medium and high frequency range is reproduced.